/****************************************************************************
 *
 * Copyright 2023 Samsung Electronics All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the License for the specific
 * language governing permissions and limitations under the License.
 *
 ****************************************************************************/
/****************************************************************************
 * arch/arm/src/armv7-a/arm_releasepending.c
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.  The
 * ASF licenses this file to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance with the
 * License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
 * License for the specific language governing permissions and limitations
 * under the License.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <tinyara/config.h>

#include <sched.h>
#include <debug.h>
#include <tinyara/arch.h>
#include <tinyara/sched.h>

#include "sched/sched.h"
#include "group/group.h"
#include "up_internal.h"
#ifdef CONFIG_TASK_SCHED_HISTORY
#include <tinyara/debug/sysdbg.h>
#endif

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/****************************************************************************
 * Name: up_release_pending
 *
 * Description:
 *   Release and ready-to-run tasks that have collected in the pending task
 *   list.  This can call a context switch if a new task is placed at the
 *   head of the ready to run list.
 *
 ****************************************************************************/

void up_release_pending(void)
{
	struct tcb_s *rtcb = this_task();

	svdbg("From TCB=%p\n", rtcb);

	/* Merge the g_pendingtasks list into the ready-to-run task list */

	if (sched_mergepending()) {
		/* The currently active task has changed!  We will need to
		 * switch contexts.
		 */

		/* Update scheduler parameters */

		// sched_suspend_scheduler(rtcb);

		/* Are we operating in interrupt context? */

		if (CURRENT_REGS) {
			/* Yes, then we have to do things differently.
			 * Just copy the CURRENT_REGS into the OLD rtcb.
			 */

			arm_savestate(rtcb->xcp.regs);

			/* Restore the exception context of the rtcb at the (new) head
			 * of the ready-to-run task list.
			 */

			rtcb = this_task();

			/* Restore rtcb data for context switching */

			up_restoretask(rtcb);

			/* Update scheduler parameters */

			sched_resume_scheduler(rtcb);

			/* Then switch contexts.  Any necessary address environment
			 * changes will be made when the interrupt returns.
			 */

			arm_restorestate(rtcb->xcp.regs);
		}

		/* No, then we will need to perform the user context switch */

		else {
			struct tcb_s *nexttcb = this_task();
#ifdef CONFIG_TASK_SCHED_HISTORY
			/* Save the task name which will be scheduled */
			save_task_scheduling_status(nexttcb);
#endif

			/* Update scheduler parameters */

			sched_resume_scheduler(nexttcb);

			/* Switch context to the context of the task at the head of the
			 * ready to run list.
			 */

			arm_switchcontext(&rtcb->xcp.regs, nexttcb->xcp.regs);

			/* arm_switchcontext forces a context switch to the task at the
			 * head of the ready-to-run list.  It does not 'return' in the
			 * normal sense.  When it does return, it is because the blocked
			 * task is again ready to run and has execution priority.
			 */
		}
	}
}
